Bad service for bad product

I bought a speaker from them and returned it within 7 days as there was a fault. Then took it back again with another problem and was send for repairs, when I went to collect it it was not ready in the time indicated then went back another time still not ready as they didn't have a driver to fetch it. Then they called me to tell me I can come fetch another one they have. Got that one and again it has the same problem that the other had that went for repairs. So I phoned within and requested refund as clearly there is something wrong with the item. Then they tell me they can only repair and not refund. Why must I have an item that I must keep sending for repairs? And drive 60 kms 2 way every time to take and fetch.